/*
 * Copyright (c) 2016-2088, fastquery.org and/or its affiliates. All rights reserved.
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 * For more information, please see http://www.fastquery.org/.
 * 
 */

package org.fastquery.util;

import java.util.HashSet;
import java.util.Objects;
import java.util.Set;

/**
 * #{#表达式} 解析
 * @author mei.sir@aliyun.cn
 */
public final class SharpExprParser {

	private SharpExprParser() {}
	
	public static Set<String> matchesNotrepeat(String str) {
		Objects.requireNonNull(str);
		
		Set<String> sets = new HashSet<>();
		
		find(str, sets);
		
		return sets;
	}
	
	private static void find(String str, Set<String> sets) {
		int startIndex = 0;
		int endIndex = 0;
		boolean loop = true;
		while (loop) {
			startIndex = str.indexOf("#{#",startIndex);
			if(startIndex != -1) {
				endIndex = str.indexOf('}', startIndex + 1);
				if(endIndex!=-1) {
					sets.add(str.substring(startIndex, endIndex + 1));
					startIndex = endIndex + 1;
				} else {
					loop = false;
				}
			} else {
				break;
			}
		}
	}
	
}
